Microbiological survey and genomic analysis of Cronobacter sakazakii strains isolated from US households and retail foods.

Cronobacter species are opportunistic pathogens that are capable of causing morbidity and mortality, particularly in infants. Although the transmission dynamics involved in Cronobacter infections remain largely unknown, contaminated powdered infant formula (PIF) has been linked to 30% of Cronobacter sakazakii cases involving invasive illness in infants. As several lines of evidence have implicated the domestic environment in PIF contamination, we undertook a microbiological survey of homes (N = 263) across the US. Cronobacter spp. and C. sakazakii were isolated from 36.1% and 24.7% of US homes, respectively, with higher recovery rates observed for floor and kitchen surfaces. Multi-locus sequence typing indicated that the dominant strain was C. sakazakii ST4, the sequence type most commonly associated with neonatal meningitis. For comparison purposes, retail foods (N = 4,009) were also surveyed, with the highest contamination frequencies (10.1%-26.3%) seen for nut products, seeds, and grains/baked goods/flours. The sequence type profile of isolates recovered from homes mirrored that of isolates recovered from retail foods, with increased representation of ST1, ST4, ST13, ST17, and ST40. Analysis of 386 whole genomic sequences revealed significant diversity. Redundancies were only observed for isolates recovered from within the same domicile, and there were no identical matches with sequences archived at the NCBI pathogen database. Genes coding for putative virulence and antibiotic resistance factors did not segregate with clinically significant sequence types. Collectively, these findings support the possibility that contamination events occurring within the home should not be overlooked as a contributor to community-onset Cronobacter infections. IMPORTANCE: Cronobacter sakazakii is an opportunistic pathogen that can cause significant morbidity and mortality in neonates. Its transmission dynamics are poorly understood, though powered infant formula (PIF) is thought to be the major transmission vehicle. How the PIF becomes contaminated remains unknown. Our survey shows that roughly 1/4 of US homes are contaminated with Cronobacter sakazakii, particularly in the kitchen setting. Our analyses suggest that the domestic environment may contribute to contamination of PIF and provides insights into mitigating the risk of transmission.

Clinical Efficacy of Topical Vitamin C on the Appearance of Wrinkles: A Systematic Literature Review.

PURPOSE: A rise in market demand for anti-aging skin care products has resulted in a proliferation of cosmeceuticals, including products that contain vitamin C. Many topicals containing vitamin C claim to reduce the appearance of wrinkles. However, these claims have not been systematically evaluated. METHODS: A systematic review of literature published between January 2015 and September 2022 was performed per PRISMA guidelines. Scopus, Web of Science, and PubMed were queried for records relevant using the following Medical Subject Heading (MeSH) terms: “Topical Vitamin C OR Ascorbic acid”, “Vitamin C efficacy”, “dermatology”, “cosmetology”, and “skin anti-aging”. Variables of interest included: study type, study location, study duration, sample size, patient description, type and ingredients of the topical formulation, outcome measurement, results, and adverse events. RESULTS: After deduplication, consideration of inclusion and exclusion criteria, and title/abstract screening, 5,428 initial records were reduced to 7 articles, including 4 meeting Level IB criteria, one meeting Level IIA criteria, and 2 meeting Level IIB criteria. Methods for assessing clinical improvements included global photodamage score, skin topography assessment, reflectance confocal microscopy (RCM) skin analysis, Dynamical Atlas, and participant self-assessment.  Conclusions: While 4 of the 7 studies met Level IB evidence, further high-quality, prospective, and comparative studies are indicated to better elucidate the role of topical vitamin C in wrinkle reduction. All the studies used vitamin C in combination with other ingredients or therapeutic mechanisms, thereby complicating any specific conclusions regarding the efficacy of vitamin C. Citation: Sanabria B, Berger LE, Mohd H, et al. Clinical efficacy of topical vitamin C on the appearance of wrinkles: a systematic literature review. J Drugs Dermatol. 2023;22(9):898-904. doi:10.36849/JDD.7332.

Memory Gaps in America: Mutational and Immunoinformatic Analysis of Evolving SARS-CoV-2 Variants of Concern and Interest.

The perpetuation of the SARS-CoV-2 pandemic has permitted the continued evolution of mutations, many of which appear to promote infectivity, transmission, and immune evasion. Critically, several derivative lineages defined as variants of concern (VOCs) and variants of interest (VOIs) have emerged in the last year that possess a constellation of highly adaptive mutations that have resulted in unprecedented propagation. To better understand the significance of these mutations, we analyzed their molecular and immunological consequences against the immunogenetic profile of the United States population using immunoinformatics to analyze in silico data. Our findings indicate that several evolving mutations in the VOCs and VOIs appear to confer immune evasion properties leading to antigenic drift, specifically for Ab-mediated and Th cell-mediated immune recognition, whereas mutations leading to evasion from innate immune mechanisms are less common in the more successful VOC strains compared with the VOIs. Importantly, several of these mutations raise concerns for the effectiveness of anamnestic responses achieved through natural infection and vaccination as well as for the utility of Ab-based therapeutic interventions. The emergence of such adaptations underscores the need for vaccine enhancements as well as the continued need to for preventative hygiene measures to help minimize transmission.

Case Report: Allergic Reactivity to Mahaleb (Prunus mahaleb) Spice in a Subject With Almond and Other Tree Nut Allergies.

BACKGROUND: Mahaleb is an aromatic spice prepared from the fruit stone of the St. Lucie Cherry that is used as a flavoring agent in traditional Turkish and Middle Eastern baking. Immunodiagnostic kits for almond, which are based on polyclonal almond-specific IgG antibodies, have been shown to demonstrate considerable cross-reactivity with mahaleb as was incidentally discovered during a cluster of allergen-related food recalls in 2015. OBJECTIVE: Though acute allergy to almond is somewhat common, allergies to mahaleb have not been previously documented. However, based on antigenic similarity observed with almond-specific IgG, it is predicted that mahaleb nut proteins would exhibit some level of cross-reactivity with almond-specific IgE and may therefore potentiate acute allergic symptoms in individuals with food allergy to almond.Case Presentation: Herein, we report on a 40-year old Caucasian female with longitudinal history of multiple tree nut allergies including allergy to almond, presenting with moderate pruritus and oropharyngeal swelling shortly following ingestion of mahaleb seed kernels. METHODS AND RESULTS: Skin-prick testing using extracts compounded from pistachio, almond, and mahaleb revealed positive wheals measuring 8, 3, and 7 mm respectfully. Indirect enzyme-linked immunosorbent assay (ELISA) using plate-bound antigens prepared from pistachio, almond, and mahaleb revealed IgG positive responses to all three targets. ELISA and Western blot analysis performed using goat anti-almond polyclonal IgG demonstrated significant cross-reactivity between almond and mahaleb, but not to pistachio. CONCLUSION: This is the first documented case of acute allergy to mahaleb, co-occurring in the context of plural tree nut allergies, providing novel evidence that mahaleb may pose a risk to nut-allergic individuals and indicating a need for awareness of spice contamination with nut and mahaleb residues.

Quantitative Detection of Chicken and Turkey Contamination in Cooked Meat Products by ELISA.

Background: Concerns about the contamination of meat products with undeclared meats and new regulations for the declaration of meat adulterants have established the need for a rapid test to detect chicken and turkey adulteration. Objective: To address this need, Microbiologique, Inc. has developed an ELISA that can quantify the presence of chicken and turkey down to 0.1% (w/w) in cooked pork, horse, beef, goat, and lamb meats. Results: This chicken/turkey authentication ELISA has an analytical sensitivity of 0.000037% and 0.000048% (w/v) for cooked and autoclaved chicken, respectively, and an analytical range of quantitation of 0.025-2% (w/v), in the absence of other meats. The assay cross-reacts with cooked duck and pheasant but does not demonstrate any cross-reactivity with cooked pork, horse, beef, goat, and lamb meats, egg, or common food matrixes. Conclusions: The assay is rapid, can be completed in 70 min, and can detect a 0.1% level of meat adulteration. Highlights: The Microbiologique Cooked Chicken/Turkey ELISA can quantitate cooked chicken/turkey in the presence of pork, horse, chicken, goat, or sheep meat to 0.1% (w/w) and is not affected by common food matrixes.

Quantitative Detection of Beef Contamination in Cooked Meat Products by ELISA.

Background: Concerns about the contamination of meat products with undeclared meats, and new regulations for the declaration of meat adulterants have established the need for a rapid test to detect beef adulteration to 0.1% sensitivity. Objective: To address this need, Microbiologique, Inc. has developed an ELISA that can quantify the presence of beef down to 0.1% (w/w) in cooked pork, horse, chicken, goat, and sheep meat. Results: The beef-authentication ELISA has an analytical sensitivity of 0.00022 and 0.00012% (w/v) for cooked and autoclaved beef, respectively, and an analytical range of quantitation of 0.025 to 2% (w/v), in the absence of other meats. Moreover, the assay is specific for cooked beef and does not cross react with common food matrixes. Conclusions: The assay is rapid, can be completed in 70 min, and can detect a 0.1% level of meat adulteration. The assay is an improvement over a previous U.S. Department of Agriculture's tested assay, which is sensitive to 1% adulteration and takes 2.5-3 h to complete. Highlights: The Microbiologique Cooked Beef ELISA can quantitate cooked beef in the presence of pork, horse, chicken, goat, and sheep meat to 0.1% (w/w) and is not affected by common food matrixes.

Quantitative Detection of Horse Contamination in Cooked Meat Products by ELISA.

Concerns about the contamination of meat products with horse meat and new regulations for the declaration of meat adulterants have highlighted the need for a rapid test to detect horse meat adulteration. To address this need, Microbiologique, Inc., has developed a sandwich ELISA that can quantify the presence of horse meat down to 0.1% (w/w) in cooked pork, beef, chicken, goat, and lamb meats. This horse meat authentication ELISA has an analytical sensitivity of 0.000030 and 0.000046% (w/v) for cooked and autoclaved horse meat, respectively, and an analytical range of quantitation of 0.05-0.8% (w/v) in the absence of other meats. The assay is rapid and can be completed in 1 h and 10 min. Moreover, the assay is specific for cooked horse meat and does not demonstrate any cross-reactivity with xenogeneic cooked meat sources.

Quantitative Detection of Pork Contamination in Cooked Meat Products by ELISA.

Recent news of many cases of adulteration of meats with pork has bolstered the need for a way to detect and quantify the unwanted contamination of pork in other meats. To address this need, Microbiologique, Inc. has produced a sandwich ELISA assay that can rapidly quantify the presence of pork in cooked horse, beef, chicken, goat, and lamb meats. We carried out a validation study and showed that this assay has an analytical sensitivity of 0.00014 and 0.00040% (w/v) for cooked and autoclaved pork, respectively, and an analytical range of quantitation of 0.05-3.2% (w/v) in the absence of other meats. The assay can measure pork contamination down to 0.1% (w/w) in the presence of cooked horse, beef, chicken, goat, and lamb meats. The assay is quick and can be completed in 1 h and 10 min.

Assessment of Avenins from Different Oat Varieties Using R5-Based Sandwich ELISA.

Gluten derived from wheat and related triticeae cereals possesses distinct amino acid sequences that provoke the immunopathogenic features of celiac disease (CD) in genetically susceptible individuals. However, the role of oat-derived gluten, or avenins, in CD pathogenesis remains a disputed matter, as evidenced by a lack in harmonized legislation regarding gluten classification in relation to gluten-free labeling. In this study, we have analyzed a panel of pure oat cultivars using a sandwich ELISA based on the R5 monoclonal antibody (mAb), which binds to canonical epitopes occurring within celiagenic peptides present in triticeae-derived gluten but reportedly not present in avenins. We have identified three varieties of oats that reproducibly bind R5 antibodies and levels indicating the presence of gluten at more than the 20 ppm gluten regulatory threshold. Nested assessment using Western blot analysis and alternative gluten detection systems corroborated these results. Collectively, these data suggest that select oat varieties may prove problematic to patients with CD and to food companies and regulatory agencies and will extend our basic understanding of current gluten detection systems.

Novel Monoclonal Antibody-Based Immunodiagnostic Assay for Rapid Detection of Deamidated Gluten Residues.

Gluten derived from wheat and related Triticeae can induce gluten sensitivity as well as celiac disease. Consequently, gluten content in foods labeled "gluten-free" is regulated. Determination of potential contamination in such foods is achieved using immunoassays based on monoclonal antibodies (mAbs) that recognize specific epitopes present in gluten. However, food-processing measures can affect epitope recognition. In particular, preparation of wheat protein isolate through deamidation of glutamine residues significantly limits the ability of commercial gluten testing kits in their ability to recognize gluten. Adding to this concern, evidence suggests that deamidated gluten imparts more pathogenic potential in celiac disease than native gluten. To address the heightened need for antibody-based tools that can recognize deamidated gluten, we have generated a novel mAb, 2B9, and subsequently developed it as a rapid lateral flow immunoassay. Herein, we report the ability of the 2B9-based lateral flow device (LFD) to detect gluten from wheat, barley, and rye and deamidated gluten down to 2 ppm in food as well as its performance in food testing.

Development and Validation of a Lateral Flow Immunoassay Test Kit for Dual Detection of Casein and ß-Lactoglobulin Residues.

Allergies to cow's milk are very common and can present as life-threatening anaphylaxis. Consequently, food labeling legislation mandates that foods containing milk residues, including casein and/or ß-lactoglobulin, provide an indication of such on the product label. Because contamination with either component independent of the other can occur during food manufacturing, effective allergen management measures for containment of milk residues necessitates the use of dual screening methods. To assist the food industry in improving food safety practices, we have developed a rapid lateral flow immunoassay test kit that reliably reports both residues down to 0.01 µg per swab and 0.1 ppm of protein for foods. The assay utilizes both sandwich and competitive format test lines and is specific for bovine milk residues. Selectivity testing using a panel of matrices with potentially interfering substances, including commonly used sanitizing agents, indicated reduction in the limit of detection by one-to fourfold. With food, residues were easily detected in all cow's milk-based foods tested, but goat and sheep milk residues were not detected. Specificity analysis revealed no cross-reactivity with common commodities, with the exception of kidney beans when present at high concentrations (> 1%). The development of a highly sensitive and rapid test method capable of detecting trace amounts of casein and/or ß-lactoglobulin should aid food manufacturers and regulatory agencies in monitoring for milk allergens in environmental and food samples.

A Novel Immunoassay Test System for Detection of Modified Allergen Residues Present in Almond-, Cashew-, Coconut-, Hazelnut-, and Soy-Based Nondairy Beverages.

A growing number of plant-based milk substitutes have become commercially available, providing an array of options for consumers with dietary restrictions. Though several of these products rival cow's milk in terms of their nutritional profiles, beverages prepared with soy and tree nuts can be a significant concern to consumers because of potential contamination with food allergens. Adding to this concern is the fact that allergen residues from plant-based beverages are modified during manufacturing, thereby decreasing the sensitivity of antibody-based detection methods. Consequently, many commercially available allergen detection kits are less effective for allergens derived from nondairy milk substitutes. To address this limitation, we developed a panel of polyclonal antibodies directed against the modified proteins present in almond, cashew, coconut, hazelnut, and soy milks and incorporated them into rapid lateral flow immunoassay tests configured in both sandwich and competitive format. The tests had robust detection capabilities when used with a panel of various brand-name products, with a sensitivity of 1 ppm and selectivity values of 3 to 5 ppm in nondairy beverages. Minimal cross-reactivity to extracts prepared from common commodities was observed. The development of a highly sensitive and rapid test specifically designed to detect trace quantities of highly modified allergen residues in plant-based, dairy-free beverages will aid food manufacturers and regulatory agencies in monitoring products for these modified allergens when testing environmental and food samples.